Effect of Heat Stress on Sargassum fusiforme Leaf Metabolome

Abstract

Temperature is a major environmental factor affecting the growth, development, and productivity of Sargassum fusiforme. We aimed to assess the metabolic processes and regulatory mechanisms in S. fusiforme during a 7-day high-temperature (27 °C and 32 °C) experiment. Changes in chlorophyll content and electrolyte leakage after high-temperature treatment were investigated. Metabolic changes in the leaves of S. fusiforme were analysed using gas chromatography–mass spectrometry. High temperatures suppressed chlorophyll content and increased electrolyte leakage. Further, a strong modulation of various metabolisms was observed: organic acids, amino acids, sugars or sugar alcohols, esters, and amines. These metabolisms were significantly enriched in ten pathways under the 27 °C treatment: aminoacyl-tRNA biosynthesis; glycine, serine, and threonine metabolism; alanine, aspartate, and glutamate metabolism; valine, leucine, and isoleucine biosynthesis; cyanoamino acid metabolism; cysteine and methionine metabolism; arginine and proline metabolism; tyrosine metabolism; citrate cycle (TCA cycle); and glucosinolate biosynthesis. The various metabolisms significantly enriched seven pathways under the 32 °C treatment, namely, alanine, aspartate, and glutamate metabolism; aminoacyl-tRNA biosynthesis; phenylalanine metabolism; tyrosine metabolism; arginine and proline metabolism; nitrogen metabolism; and isoquinoline alkaloid biosynthesis. These changes in metabolic pathways may contribute to the tolerance and adaptability of S. fusiforme to high-temperature stress.